Sonography vs. excretory urography in acute flank pain

A prospective study compared the diagnostic accuracy of sonography and excretory urography in determining the cause of acute flank pain in 61 patients. Forty-one patients had urinary tract stone disease. Of these, five had nonobstructing renal stones and 36 had obstructing stones. A correct diagnosis was made by urography in 85% and by sonography in 66%. Small stones at the ureterovesical junction were more accurately diagnosed by sonography (79%) than by urography (68%). In all the patients where sonography failed to detect the offending stone, the stone was calcified and evident on the plain radiographs. There were no false-positive diagnoses in the patients clinically judged to have passed a renal stone (nine patients) or whose pain was arising outside of the urinary tract (five patients). Neither sonography (17%) nor urography (50%) was accurate in diagnosing acute pyelonephritis in the six patients with this diagnosis. Although sonography is not as accurate overall as urography in acute flank pain, it is a viable alternative in those with recurrent renal colic due to stone disease and in the pregnant patient.     

Ultrasonography versus excretory urography: value in urological disease

Considerable savings in cost and some reduction in gonad dose and contrast medium allergy can be expected if excretory urography can be replaced by real-time ultrasonography as the first examination in upper urinary tract disease. For one year, all patients referred for excretory urography (UG) are first examined with real-time ultrasonography (US) to establish whether UG can be completely replaced by US, or the indications for which US should be the first examination of choice. The results in 200 consecutive patients indicate that both methods sometimes fail, but not in the same patients. A combination of the two may be unbeatable, but uneconomical. The results obtained over one year may give the answer. Hopefully studies at other centres will be initiated to increase the size of the case material.     

Patients with acute flank pain: comparison of MR urography with unenhanced helical CT

PURPOSE: To compare unenhanced helical computed tomography (CT) and magnetic resonance (MR) urography, by using T2-weighted and contrast material-enhanced T1-weighted imaging to examine patients with acute flank pain, with reference to excretory urography and final clinical diagnosis. MATERIALS AND METHODS: Forty-nine patients underwent CT, MR urography (with T2-weighted and gadopentetate dimeglumine-enhanced T1-weighted sequences), and excretory urography. CT and MR urographic findings were evaluated separately and independently by two radiologists each (CT, observers A and B; MR urography, observers C and D) for the presence, cause, level, and degree of obstruction. The final conclusive diagnosis was based on the combination of excretory urographic, clinical, and interventional results. RESULTS: At final diagnosis, 32 (65%) patients were found to have ureteral stones causing unilateral obstruction. In ureteral stone detection, the sensitivity and specificity of CT were 90.6% (29 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer A) and 90.6% (29 of 32 patients) and 94.1% (16 of 17 patients), respectively (observer B), while those of MR urography were 93.8% (30 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer C) and 100.0% (32 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer D). Spearman correlation coefficients for stone size at CT were 0.76 (P <.001) and 0.75 (P <.001) and at MR urography, 0.49 (P =.005) and 0.51 (P =.004). CONCLUSION: In routine clinical practice, CT is the modality of choice in the evaluation of patients with acute flank pain. MR urography is an accurate and suitable alternative imaging technique in selected patients.     

Computed tomography versus intravenous urography in diagnosis of acute flank pain from urolithiasis: a randomized study comparing imaging costs and radiation dose

The equivalent sensitivity of non-contrast computed tomography (NCCT) and intravenous urography (IVU) in the diagnosis of suspected ureteric colic has been established. Approximately 50% of patients with suspected ureteric colic do not have a nephro-urological cause for pain. Because many such patients require further imaging studies, NCCT may obviate the need for these studies and, in so doing, be more cost effective and involve less overall radiation exposure. The present study compares the total imaging cost and radiation dose of NCCT versus IVU in the diagnosis of acute flank pain. Two hundred and twenty-four patients (157 men; mean age 45 years; age range 19-79 years) with suspected renal colic were randomized either to NCCT or IVU. The number of additional diagnostic imaging studies, cost (IVU A$136; CTU A$173), radiation exposure and imaging times were compared. Of 119 (53%) patients with renal obstruction, 105 had no nephro-urological causes of pain. For 21 (20%) of these patients an alternative diagnosis was made at the initial imaging, 10 of which were significant. Of 118 IVU patients, 28 (24%) required 32 additional imaging tests to reach a diagnosis, whereas seven of 106 (6%) NCCT patients required seven additional imaging studies. The average total diagnostic imaging cost for the NCCT group was A$181.94 and A$175.46 for the IVU group (P < 0.43). Mean radiation dose to diagnosis was 5.00 mSv (NCCT) versus 3.50 mSv (IVU) (P < 0.001). Mean imaging time was 30 min (NCCT) versus 75 min (IVU) (P < 0.001). Diagnostic imaging costs were remarkably similar. Although NCCT involves a higher radiation dose than IVU, its advantages of faster diagnosis, the avoidance of additional diagnostic imaging tests and its ability to diagnose other causes makes it the study of choice for acute flank pain at Christchurch Hospital.     

Digital radiography versus conventional radiography during excretory urography: our experience

The authors describe a computed radiographic system employed to generate and archive digital images in intravenous urography. For each exposure the system produces two digital images: the first (left image) simulates a conventional screen-film radiograph, the second (right image); enhances some spatial frequencies and emphasizes the margins of the structures. These images can be modified in their chief parameters and then printed by a laser-printer and archived on optical disks. Four experienced radiologists evaluated digital images with regard to some chief diagnostic parameters and, in 50 patients, they compared digital images with conventional screen-film radiographs and submitted the results to statistical analysis. For some of the chosen parameters, particularly for the evaluation of renal margins before and after contrast medium injection, digital images gave statistically better results than conventional films, while, no statistically significant different was observed for the other parameters. From the results of this preliminary study digital radiography was found to be useful in intravenous urography by reducing the patient's exposition dose, by always obtaining images of good quality, and by enhancing some particular features of the standard image; on the other hand there were many unsolved problems regarding the communicating and archiving system (PACS), because of the slowness of the image transfer procedure, difficulties in data transmission and complexity of referential procedures.     

Modified excretory urography in prehysterectomy patients

A retrospective (520 patients) and prospective study (100 patients) of prehysterectomy patients was done to determine the role of preoperative excretory urography. Potentially useful information was provided by the urogram in only a small number of patients (7.4%). It is arguable whether or not preoperative intravenous urography should be done in these patients. However, since most of these patients routinely undergo this study, we suggest that a curtailed urogram consisting of a KUB film, a postinjection 15-minute prone film, and a supine film of the contrast-filled urinary bladder is adequate for preoperative screening, thereby minimizing cost and radiation to the patient.     

Emergency excretory urography in blunt abdominal trauma

In a prospective study the authors correlated the degree of hematuria and of blunt abdominal trauma with the results of emergency excretory urography. Urograms were obtained for 37 patients who presented with blunt abdominal trauma, no gross hematuria and at least five erythrocytes per high-power field (hpf) on microscopic urinalysis. Microscopic hematuria was defined as an erythrocyte count of more than 5 and fewer than 50 per hpf. Major trauma was defined as shock (systolic blood pressure of less than 90 mm Hg), fracture of the lumbar spine, the pelvis or the lower ribs, ecchymosis in the flank or acute abdominal injury. Contusions and small subcapsular hematomas were defined as nonsignificant renal injuries; all other renal injuries were defined as significant. Of 17 patients with minor blunt abdominal trauma 14 had fewer than 50 erythrocytes per hpf; none of these had a significant renal injury, whereas 1 of the 3 with more than 50 erythrocytes per hpf did have a significant injury. Of 20 patients with major trauma 5 had a significant renal injury. The authors conclude that microscopic hematuria associated with blunt abdominal trauma but without shock or major nongenitourinary injury does not warrant routine excretory urography.     

Fluid restriction before excretory urography.

Despite a lack of hard evidence, many radiologists continue to support the use of fluid restriction before urography. Based on increasing the urinary contrast medium concentration, this has been shown to be a poor index for renal opacification. The usual overnight restriction produces no significant change in urine osmolality or opacification. Effective fluid restriction may produce a just detectable increase in pyelographic density but the nephrogram in unaffected, even by active hydration. Fluid restriction may occasionally result in inadvertent dehydration with serious or fatal reactions. Since it is ineffectual in improving the urogram and potentially hazardous, it should be abandoned.     

Limited use of hypertensive excretory urography

Clinical experience indicates that hypertensive excretory urography is not a satisfactory screening examination to detect patients having hypertension due to renal artery stenosis. Review of the Cooperative Study data indicates the false negative rate for screening was 21.8%. In addition, the prevalence of hypertension caused by renal artery stenosis appears quite low, in the range of 1–3%. Since the objective is to identify patients who will benefit from surgery, clinical sorting strategy should focus on evaluating patients as surgical candidates, not as having the disease. Once that is done, pharmacodynamic renal arteriography is recommended as the first imaging examination to find the renal artery lesion and determine its hemodynamic significance.     

The value of post-void radiographs in excretory urography

For years, urologists and radiologists have had differing opinions on the value of post-void radiographs in excretory urography. This report is based on a questionnaire sent to the members of the Association of University Urologists and the Society of Uroradiologists. Satisfactory evaluation of bladder function by the use of post-void radiographs is not always possible. Nevertheless, such radiographs have value in selected cases and often play a major role in determining future therapy.